Wallraf-Richartz-Museum & Fondation Corboud Cologne

One of Germany's finest art museums, the Wallraf-Richartz presents a primo collection of European art from the 13th to the 19th centuries in a minimalist cube designed by the late OM Ungers. All the marquee names are here – Rubens and Rembrandt to Manet and Monet – along with a prized sampling of medieval art, most famously Stefan Lochner's Madonna in Rose Bower, nicknamed the 'Mona Lisa of Cologne'.